Electrical power steering (EPS) systems in vehicles use an electric motor connected to the steering gear or steering column that is electronically controlled to provide a torque to assist a driver in steering the vehicle. EPS systems typically include an electric motor and controller that receives steering torque information from a torque sensor and controls the motor to transmit assist torque to the wheels, e.g., by applying the torque to the steering column. One type of motor is a Permanent Magnet (PM) brushless motor.
The controller typically controls the EPS motor by generating duty cycle signals for each motor phase, e.g., using pulse width modulation (PWM), which are used to provide phase voltage signals to the motor. As malfunctions in generating such signals can compromise the effectiveness and safety of EPS systems, diagnostic functions may be provided to monitor signal generation.